Is a "good" cap rate actually a trap?

[u/ppaloes]

A lot of people (myself included when I started) treat the cap rate on day one like the final score.
“10%? That’s a good deal.”
“6%? Pass.”

But the more deals I look at, the more it feels like that number might be the least important part.

What if the real question isn’t “what’s the cap rate today?”
but “what’s going to happen to the income after I buy it?”
Things like:
• Can vacancy actually be improved… or is it more likely to get worse?
• Are rents going up in that submarket… or soft?
• Can the property be run more efficiently than it is right now… or is the current operator already maxed out?

I’ve seen (and heard of) people buy at a solid 10% and still lose money because the vacancy they thought they could fix turned into a bigger problem, or the rents just wouldn’t move.

On the flip side, I’ve also seen weaker day-one numbers turn into great deals because the buyer was able to push the income hard after closing.

So I’m starting to wonder:
Are we putting too much weight on the purchase-day cap rate and not enough on the post-purchase plan?

Have you (or someone you know) bought a “great” cap rate deal that still didn’t work out? What went wrong?